The present invention relates to a selectively engageable shaft lock and drive device which can be used in applications such as steerable aerodynamic surfaces on rockets, missiles, bombs or the like. Typical shaft lock and drive devices in use have two states: a “storage” state in which the shaft and drive mechanism is locked in place and an “in use” state where the shaft lock is disengaged and the drive device operates to control the shaft and, in turn the connected aerodynamic surface. In typical shaft lock and drive devices currently in use, once the shaft lock is disengaged it cannot be returned to the “storage” or “engaged state.” This is primarily due to the fact that current shaft lock and drive devices typically use pyrotechnic bolts, fasteners or the like to engage the shaft lock. Once the pyrotechnic bolts are destroyed (as the shaft lock is disengaged), the shaft lock can never return to the “storage” or “engaged” state.
Another problem addressed by the current invention relates to the inability of the prior art shaft lock and drive devices to be fully tested prior to deployment. The current invention provides for a reversible shaft lock and drive device which allows the drive device to be fully operated and tested while the rocket, missile, etc. is in a state other than flight.
Another purpose of this invention is to provide a single mechanism to both maintain the shaft lock in the engaged position and to drive the shaft once the rocket, missile, etc. is in flight. This results in a fundamental cost and weight savings versus a separately operated device, regardless of type (motor, pyrotechnic, gas generator, etc.).